Search Results (1,666)

Accurate parameterization of the photovoltaic single-diode model is usually obtained from complete current–voltage (I-V) measurements. However, full I-V curve tracing is not always available in real monitoring environments, where the most accessible variables are irradiance and module temperature. This paper proposes a hybrid methodology for reconstructing the five parameters of the single-diode model from irradiance and temperature data. The method first estimates the maximum-power point and the remaining remarkable points of the I-V curve as well as the photocurrent ($I_{ph}$) through regression models calibrated on measured data. These predicted points are sufficient to solve the SDM equation. A numerical approach is then used to identify the five SDM parameters while enforcing physical admissibility constraints. The method is validated using NREL outdoor datasets from three locations and several photovoltaic technologies. The results show that the maximum-power current is estimated with very high reliability, with $R^2$ values close to unity in almost all cases. Voltage estimation is less stable and depends more strongly on technology and temperature sensor location. The reconstructed I-V curves are physically admissible for most crystalline silicon, HIT, and CdTe modules, whereas CIGS and amorphous silicon modules exhibit lower admissibility. The proposed method should therefore be understood as an environmental-data-driven reconstruction tool when complete I-V curves are unavailable, rather than as a replacement for direct full-curve fitting techniques such as TSLLS or Reduced Form. Full article

In this study, a novel SiC/rGO nanocomposite-modified glassy carbon electrode (SiC/rGO/GCE) was developed as a simple, cost-effective, and efficient electrochemical platform for metronidazole (MTZ) detection. The combination of silicon carbide (SiC) and reduced graphene oxide (rGO) provides a favorable interface with a high electroactive surface area, efficient electron transfer, and enhanced electrocatalytic activity. The mor-phology and surface characteristics of the modified electrode were investigated by scan-ning electron microscopy (SEM), while its electrochemical properties were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The results confirmed successful electrode modification and improved electron-transfer kinetics compared with the bare GCE. The main experimental parameters were systematically optimized, with the optimum conditions established at pH 10, an accumulation time of 300 s, and an accu-mulation potential of 0.5 V. Under these conditions, the SiC/rGO/GCE exhibited a broad linear response to MTZ over the concentration range of 5–5000 µmol/dm³, with a detection limit of 0.5 µmol/dm³ (S/N ≥ 3). The enhanced analytical performance is attributed to the synergistic contribution of rGO and SiC, where rGO promotes rapid electron transport and provides a large electroactive surface, while SiC contributes additional active sites and structural stability. The sensor was successfully applied to pharmaceutical samples, providing recoveries of 99.85–102.29% with RSD values below 2%. These results demon-strate the practical potential of the proposed sensor for reliable MTZ determination. Fur-ther validation in food and biological matrices and comparison with reference chromato-graphic methods will be necessary to establish its broader analytical applicability. Full article

Tunable external cavity diode lasers (ECDLs) are core light sources for portable quantum precision measurement, offering narrow linewidth, wide tuning range, and high spectral purity. This review systematically summarizes the research progress of ECDLs for portable quantum applications, classifying mainstream configurations into Littrow, Littman, fiber grating, and filter types. The structural principles, performance characteristics, and recent breakthroughs of each type are elaborated, with in-depth analysis of the trade-offs among tuning range, linewidth, side-mode suppression ratio (SMSR), and output power. Key progress in miniaturization and integration is highlighted, focusing on MEMS-driven tuning and silicon waveguide hybrid integration technologies, which address the conflict between performance and portability. Current challenges including mode hopping, thermal stability, and packaging loss are discussed, and future directions such as multi-band extension, isolator-free frequency stabilization, and AI-assisted control are prospected. This work provides a systematic reference for the development of compact, high-performance ECDLs toward field-deployable quantum sensors. Full article

Underwater wireless optical communication (UWOC) has emerged as a key technology for high-speed, low-latency data transmission in aquatic environments, enabling applications in autonomous underwater vehicles (AUVs), remotely operated vehicles (ROVs), subsea sensor networks, and the Internet of Underwater Things (IoUT). This paper reviews photodetector technologies that shape UWOC system performance, covering both mature and emerging detector classes. We discuss the operating principles, key parameters, and practical trade-offs of photomultiplier tubes (PMTs), p-i-n photodiodes (PINs), avalanche photodiodes (APDs), single-photon avalanche diodes (SPADs), and silicon photomultipliers (SiPMs/MPPCs). We also present emerging photodetector technologies, including perovskite-based structures, SiC photoelectrochemical devices, scintillating optical fibers, and photovoltaic solar cells. A comparative analysis of reported UWOC experiments reveals a clear sensitivity–bandwidth trade-off among detector technologies: PIN-based receivers achieve the highest data rates (up to 25 Gbps) but are generally restricted to short-range links, whereas SPAD- and SiPM-based receivers provide sensitivities below −80 dBm and support transmission distances exceeding 200 m, at the cost of moderate data rates. The findings indicate that SiPM/MPPC arrays currently offer the most promising compromise between sensitivity and data rate for long-range UWOC applications. Full article

Group III-nitride semiconductors (GaN, AlN, InN) serve as foundational materials for modern optoelectronics, high-frequency microelectronics, and next-generation energy harvesting devices. However, traditional high-temperature epitaxy (>700 °C) introduces severe thermal stress, high dislocation densities, and fundamental incompatibility with flexible substrates or CMOS back-end-of-line (BEOL) processes. Plasma-enhanced atomic layer deposition (PEALD) provides a disruptive, ultra-low thermal budget (<300 °C) pathway for atomic-scale precision growth and conformal coating. This review systematically summarizes recent frontiers in PEALD-synthesized Group III-nitrides and 2D/3D polar heterostructures. First, we dissect the microscopic nucleation kinetics, surface bond reconstruction, and impurity suppression mechanisms across diverse substrates, including Si, sapphire, quartz, metals, and flexible polymers. Next, we highlight 2D template-assisted van der Waals epitaxy on graphene and MoS2, and elucidate polarization-driven dipole interactions and band alignment engineering at 2D/3D polar interfaces (e.g., α-In₂Se₃, Janus MoSSe). Furthermore, we comprehensively discuss innovative applications in advanced photovoltaics (as electron transport and passivation layers in perovskite and quantum dot-sensitized solar cells), silicon-based microcavity lasers, high-electron-mobility transistors (HEMTs), and flexible multimodal sensors. Finally, key technological challenges—including the low-thermal-budget paradox, wafer-scale uniformity, and deposition throughput—are addressed alongside future perspectives in area-selective ALD and neuromorphic computing, presenting a cohesive blueprint from underlying physics to macroscopic system integration. Full article

Main memory carries data outside the processor’s trust boundary, so commodity systems-on-chip (SoCs) increasingly encrypt it; yet, in-line memory encryption engine itself becomes a differential power analysis (DPA) target whose key, if recovered, unlocks all of dynamic random-access memory (DRAM). We present PACE, a page-adaptive, cache-anchored memory encryption engine for RISC-V that makes nth-order DPA resistance practical and keeps cryptographic latency off the cache eviction critical path. PACE inserts a TileLink adapter between the last-level cache and the memory port and applies, per physical page, one of four policies (plaintext/confidentiality/confidentiality+integrity/+masking-order-d) selected from RISC-V page table bits through a memory-mapped control plane. Confidentiality uses counter mode whose per-line keystream is precomputed during cache residency; integrity is tree-free at the embedded operating point via on-chip counters and tags, with a live split counter block-MAC Bonsai Merkle tree for scale-out. DPA resistance is layered: ISAP-style fresh re-keying caps the data complexity per key at $q\approx 1$, and domain-oriented masking (DOM, d + 1 shares) protects the sole key processing block to order d. We implement PACE in Chisel on a Rocket SoC (Chipyard) and evaluate it with open-source tooling. A deterministic TileLink-level harness proves ciphertext-in-memory and detects tamper/replay/splice, and the live Tier-B engine (DRAM counters and per-line message authentication codes (MACs) plus an on-chip-rooted block-MAC tree) is validated from end to end on full Rocket and BOOM SoCs and on the FPGA; the masked Ascon-p S-box is proven order-d secure (d = 1, 2) under a glitch- and transition-aware model by three independent formal tools (COCO, PROLEAD, and SILVER, the last also deciding the full composability lattice and confirming exact glitch-robust order-2 probing security), with COCO extending the exact verdict to the highest synthesized order d = 3 (secure at probing orders 1–3); a simulated trace correlation power analysis (CPA) recovers the full key from an unprotected core and is defeated by masking, with a mutual information analysis confirming the $N\propto {\sigma }^{2(d+1)}$ trace amplification law. We further realize PACE on field-programmable gate array (FPGA) silicon: the engine plus an on-chip ring oscillator power sensor is placed, routed, timing-closed at 100 MHz, and programmed on a Xilinx XC7Z020, and we drive a fixed-vs-random Test Vector Leakage Assessment (TVLA) campaign read back entirely over a JTAG (Joint Test Action Group). A multi-core configuration and a Linux control-plane driver are likewise validated. Across synthetic access patterns and named application kernels (AES, SHA-256, matrix multiplication, pointer chasing) on both in-order Rocket and out-of-order BOOM, application-level overhead is within measurement noise of plaintext for cache resident workloads (masking, in particular, is cycle-identical to plain confidentiality), and we characterize the cost of each policy, masking order, and re-keying interval, demonstrating side-channel-hardened memory encryption on open RISC-V hardware. Full article

Silicone oil is a promising dielectric coolant for battery immersion cooling, yet the ability of commercially available conductivity sensors to detect battery-related contamination remains poorly quantified. In this study, simulated carbonaceous particles, electrolyte, and mixed solid–liquid contaminants were introduced into silicone oil under controlled conditions using a closed-loop circulation platform, and conductivity was monitored in real time. Pristine silicone oil exhibited a baseline conductivity near the instrumental detection limit (approximately 1.26 μS·cm⁻¹). No measurable conductivity increase was observed for particle concentrations up to 10 g·L⁻¹ or electrolyte additions up to 3.0 vol%. Only under an intentionally extreme condition involving 20 vol% electrolyte and vigorous mixing were transient conductivity spikes of 350–550 μS·cm⁻¹ detected. Thus, within the application-relevant concentration range examined, conductivity monitoring showed limited sensitivity to progressive contamination. These findings concern the response of a commercial low-field conductivity sensor and do not constitute a complete assessment of leakage current, dielectric strength, or full thermal-runaway conditions. Full article

Autonomous robotic systems designed for extraterrestrial in situ resource utilization (ISRU) will play a central role in enabling a sustained human presence on the Moon and Mars. These robots are expected to perform tasks such as regolith excavation, water extraction, oxygen production, and propellant generation under extremely harsh environmental conditions, including large temperature variations, abrasive dust, high radiation levels, and significant communication delays with Earth. Consequently, their onboard electrical systems must operate with high reliability, autonomy, and fault tolerance. A critical enabling technology for these systems is the isolated power conversion architecture, which distributes energy from primary power sources to multiple robotic subsystems, including mobility actuators, drilling systems, sensors, computing units, and thermal management modules. Future lunar and Martian missions are expected to rely on a combination of alternative energy sources, including solar photovoltaic arrays with energy storage, fuel cells, radioisotope power systems, and nuclear surface power reactors, which can provide continuous and high-density energy independent of sunlight availability. These diverse power sources require flexible and highly efficient isolated DC–DC power conversion architectures capable of managing wide input voltage ranges while ensuring electrical isolation, safety, and system stability across distributed robotic platforms. This literature review surveys recent developments in autonomous isolated power conversion architectures suitable for lunar and Martian resource extraction robots. The review examines advanced converter topologies such as resonant converters, phase-shifted full-bridge converters, dual-active bridge converters, and modular multiport power converters designed for high efficiency, high power density, and scalable power distribution. Emphasis is placed on converter architectures capable of interfacing with nuclear-powered systems and other high-energy-density sources while supporting distributed loads in robotic mining and processing systems. In addition, the paper reviews emerging autonomous control strategies, including adaptive digital control, intelligent power management, fault detection and self-recovery mechanisms, and distributed power architectures capable of maintaining stable operation under dynamic load conditions. The role of wide-bandgap semiconductor technologies, including silicon carbide (SiC) and gallium nitride (GaN), is also examined, highlighting their potential to enable higher switching frequencies, improved efficiency, reduced system mass, and enhanced thermal performance in vacuum environments. Finally, system-level considerations for integrating isolated power conversion within robotic ISRU platforms are discussed, including redundancy strategies, power bus architectures, electromagnetic compatibility, thermal management, and long-duration reliability requirements. By consolidating advances across power electronics, autonomous control, and space power systems, this review identifies key research gaps and outlines design directions for next-generation autonomous power conversion systems capable of supporting scalable lunar and Martian resource extraction infrastructures powered by both renewable and nuclear energy sources. Full article

A technological approach to the formation of a 3D nanocomposition material based on hierarchical porous nickel oxide nanoparticles incorporated into porous silicon with a dendritic porous structure is proposed. Porous silicon was used as a 3D porous template, in the presence of which porous hierarchical nickel oxide nanoparticles were synthesized using a “green” synthesis method followed by annealing in an oxygen-containing atmosphere. The resulting materials were characterized using scanning electron microscopy, transmission electron microscopy, X-ray spectral microanalysis, X-ray diffraction, and the BET method. The potential of a developed composition based on porous hierarchical nickel and silicon oxide nanoparticles to enhance the sensitivity of adsorption gas sensors was assessed using impedance spectroscopy in the presence of a probe gas (isopropanol). Gas sensitivity measurements were conducted at room and elevated temperatures in the frequency range from 100 Hz to 500 kHz. Differences in the dependences of the real part of impedance on the imaginary part were revealed for the porNiO-porSi composition in Nyquist coordinates. The results are discussed in terms of percolation theory and fractal organization. Full article

Achieving precise microstructure control in composite dielectric layers remains a key challenge for enhancing the sensitivity and reducing the power consumption of flexible capacitive sensors. In this work, an ultrasonic needle-induced acoustic streaming strategy is proposed to regulate the spatial distribution of Fe particles within a silicone matrix, enabling controllable particle migration and aggregation in liquid silicone. Multiphysics simulations reveal that, at an excitation frequency of 75.49 kHz, Fe particles are effectively driven toward the ultrasonic focal region, forming a tunable microstructure. Experimental results confirm that this method enables precise morphological control of the composite dielectric layer. The composite with 25 wt% Fe exhibits the highest measured relative permittivity of about 3.45, enabling a capacitive sensor sensitivity of 0.423 kPa⁻¹ in the 0–1 kPa range. After acoustic-streaming optimization and integration into a four-unit capacitive array, the device achieved 0.509 kPa⁻¹ sensitivity, retained 92.04% of its response after 5000 cycles at 3 kPa, and maintained 97.8% of its initial capacitance after 24 h. The proposed approach provides an effective route to improving sensor performance through microstructure engineering while maintaining low electrical loss. This work not only advances the design of high-performance functional composites but also expands the application of acoustic streaming techniques in low-power flexible electronics. Full article

Photoelectric intelligent sensor chips have become a key technology for next-generation intelligent sensing by integrating photonic devices, electronic circuits, and artificial intelligence algorithms. Recent advances in silicon photonics, two-dimensional materials, heterogeneous integration, and intelligent signal processing have significantly improved their sensitivity, response speed, and integration capability. This review presents a comprehensive overview of photoelectric intelligent sensor chips from fundamental principles to system-level applications. The operating mechanisms, device architectures, fabrication technologies, and photonic integration strategies are summarized, followed by recent progress in industrial, medical, and intelligent sensing applications. Current technical challenges, including material quality, heterogeneous integration, power consumption, and intelligent data processing, are also discussed. Finally, future trends toward highly integrated, low-power, and AI-enabled sensing systems are highlighted. This review provides a concise reference for the development of next-generation photoelectric intelligent sensor chips and their practical applications. Full article

This work presents the design, development, and experimental validation of an inductive sensing system for monitoring prosthetic socket fit variations caused by residual limb volume fluctuations. The system aims to reduce the risk of discomfort and tissue injury by measuring the distance between the outer rigid socket and the inner silicone elastomeric liner worn in direct contact with the residual limb. The sensing architecture consists of a portable data acquisition unit, an LC resonator sensor mounted on the inner surface of the rigid socket, and a magnetic silicone target attached to the external surface of the liner. Multiple configurations of LC resonators and magnetic targets were designed and evaluated. The results indicate that a medium-sized coil (outer diameter = 28 mm, capacitance = 181 pF) combined with a 1 mm thick silicone target made of Ecoflex™ 00-50 with 70 wt% NdFeB microparticles provides the most stable and sensitive performance. Experiments demonstrated stable distance detection up to 7 mm, with the resonant-frequency shift (relative to the baseline condition) varying from −31.37 kHz at 0 mm to −2.94 kHz at 7.00 mm, for a total shift range of 29.84 kHz. Environmental tests showed minimal drift, with frequency variations below 0.40 kHz across temperature (25–60 °C) and humidity (50–90% RH) changes. In vitro validation using a high-fidelity residual limb simulator and an adjustable socket reproduced controlled residual limb volume variations of 300 mL (i.e., +7.5%), resulting in repeatable resonant-frequency changes within 3.15–3.17 MHz with measurement variability ($u_A$, Type A) below 0.13 kHz. Full article

Topological photonics provides a robust framework for controlling light, with edge states offering immunity to disorder. However, utilizing this stability for practical sensing remains a challenge, as conventional high-sensitivity photonic crystal sensors suffer common imperfections. Here, we numerically design a topological photonic crystal sensor for THz refractive-index detection. The silicon-based structural slab is engineered, showing a wide photonic bandgap (PBG). By breaking the inversion symmetry, two structures with trivial and nontrivial topological phases are constructed. Due to their opposite valley Chern numbers, the topologically protected edge states can be formed at the interface. Such edge states were further integrated with the resonant cavities, so that the resonant frequencies were observed in transmittance property, forming a stable cavity–edge states coupling channel for refractive-index sensing. Numerical results demonstrate strong suppression of transmission distortion induced by boundary defects, verifying favorable topological robustness of the proposed architecture. The structure exhibits linear refractive-index response with a simulated sensitivity of 1.9 THz/RIU, outperforming conventional photonic crystal sensors in numerical comparison. This work merges topological stability of edge states with high sensitivity response of resonant frequency, offering a theoretical candidate for robust biosensing and chemical detection. Full article

Geoelectric field observations play a vital role in geophysical exploration, geological disaster early warning, and underground resource detection. Traditional contact non-polarisable electrodes, which require burial and electrolyte coupling, are hindered by several issues, such as limited adaptability to challenging terrain, significant electrode potential drift, and high susceptibility to environmental interference. Existing non-contact electric field sensors often exhibit insufficient coupling capacitance, poor impedance matching for ultra-weak high-impedance signals, and inadequate low-frequency noise suppression, rendering them unsuitable for the precise acquisition of natural microvolt-level geoelectric field signals. To address these challenges, this study introduces an innovative non-contact geoelectric field sensor with a three-layer composite structure. The sensor operates based on the principle of a parallel-plate capacitor, with a conductive silver paste layer at the top acting as the signal acquisition electrode plate, which forms an equivalent parallel-plate capacitance model with the ground to achieve non-contact capacitive coupling for geoelectric field detection. The intermediate layer uses lead zirconate titanate (PZT) piezoelectric ceramics as a support medium with a high dielectric constant. At the bottom is a silicon-based, flexible, sensitive ground-contacting layer with high elasticity, which allows it to adapt to micro-level surface irregularities, eliminating air gaps between the electrode plate and the ground, increasing plate-to-ground coupling capacitance, and ensuring the stability of the capacitance. The three-layer structure was created using a dry-press sintering integration approach, which eliminates interlayer bonding materials while ensuring consistent dielectric performance and efficient charge transfer. Additionally, a specialised signal-conditioning circuit was designed to match the ultra-high-impedance sensitive unit, utilising the ADA4528-2 ultra-low-noise precision operational amplifier, which achieved low-loss conversion and strong noise suppression for ultra-weak high-impedance charge signals. The circuit simulation results demonstrate that the designed circuit achieves an input impedance of no less than 10 TΩ, an effective operating bandwidth from 0.02 Hz to 20 kHz, and a voltage noise density lower than 1.5 μV/√Hz at 10 Hz, fully covering the ultra-low-frequency effective band of natural geoelectric fields. Field experiments comparing artificial and natural field signals revealed that the proposed sensor could be quickly deployed by simply attaching it to the ground without burial. Its time-domain waveform consistency and frequency-domain component matching were nearly identical to those of commercial standard solid non-polarisable electrodes, with a cross-correlation coefficient greater than 0.98, indicating no significant potential drift or power-frequency interference. By structurally eliminating the inherent electrode potential difference, the sensor offers advantages such as ease of deployment, strong environmental adaptability, high precision for weak signal acquisition, and excellent engineering substitutability. It is well suited for long-term geoelectric field observations in complex field scenarios, including deserts, Gobi areas, and frozen soil regions, and provides a high-performance, novel sensing solution for geoelectric field detection in extreme environments. Full article